Reference Label Generation Rules for the Gurmukhi Script

Overview

This document specifies a reference set of Label Generation Rules (LGR) for the Gurmukhi script for the second level. The starting point for the development of this LGR can be found in the related Root Zone LGR [RZ-LGR-4-Guru]. For details and additional background on the script, see "Proposal for a Gurmukhi Script Root Zone Label Generation Ruleset (LGR)" [Proposal-Gurmukhi]. The format of this file follows [RFC 7940].

Repertoire

The repertoire contains 56 codepoints for letters used by the Punjabi language written using the Gurmukhi script. Punjabi ([EGIDS] level 2) is the only language currently using the Gurmukhi script. The repertoire is a subset of [Unicode 6.3]. For more detail, see Section 5, "Repertoire" in [Proposal-Gurmukhi]. (The proposal cited has been adopted for the Gurmukhi script portion of the Root Zone LGR.)

For the second level, the repertoire has been augmented with the ASCII digits, U+0030 (0) to U+0039 (9), and U+002D (-) HYPHEN-MINUS for a total of 67 repertoire elements.

Code points outside the Gurmukhi script that are listed in this file are targets for out-of-script variants and are identified by a reflexive (identity) variant of type "out-of-repertoire-var". They do not form part of the repertoire.

Each code point or range is tagged with the script or scripts that the code point is used with, one or more tag values denoting character category, and one or more references documenting sufficient justification for inclusion in the repertoire, see "References" below. Comments identify alternate names for some code points.

Variants

This reference LGR is designed for use in zones shared by more than one script. Where appropriate, cross-script variants have been defined to mutually exclude labels from different scripts that could otherwise be substituted by the users. Once a label has been delegated for one script, any variant labels from other scripts consisting of cross-script variants would be blocked. Any label containing at least one code point that is not a cross-script variant would be considered distinct. Because of that, even large numbers of defined cross-script variants generally do not lead to a high percentage of labels experiencing a collision.

The Gurmukhi and Devanagari scripts are closely related to each other and there are many code points in both scripts which can be confused with code points in the other script. Five sequences of Devanagari code points are defined as variants of single Gurmukhi code points. Additional cross-script variant analysis identified a smaller set of code points from the Bengali script. Where these can cause confusion even to a careful observer, they have been defined as variants. There are no in-script variants defined for Gurmukhi. See Section 6, "Variants" in [Proposal-Gurmukhi].

Digit Variants: The Gurmukhi reference LGR does not include native digits, so there are no variants defined.

Variant Disposition: All variants are of type “blocked”, making labels that differ only by these variants mutually exclusive: whichever label containing either of these variants is chosen earlier would be delegated, while any other variant labels should be blocked.

This LGR does not define allocatable variants.

The specification of variants in this reference LGR follows the guidelines in [RFC 8228].

Character Classes

Gurmukhi is an alphasyllabary and the heart of the writing system is the akshar. This is the unit which is instinctively recognized by users of the script. The elements of the writing system consist of Consonants, Implicit Vowel Killer: Halant, Vowels, Bindi, Tippi, Addak, Nukta and Visarga.

Consonants: Gurmukhi consonants contain an implicit vowel schwa /ə/. They are also used without any modification to represent consonant sounds without an implicit /ə/ vowel More details in Section 3.3.1, "The Consonants" in [Proposal-Gurmukhi].

Virama: Unlike the Halant in other Neo-Brahmi scripts, U+094D ( ् ) GURMUKHI SIGN VIRAMA is not used in general to strip a consonant letter’s implicit vowel. The Virama is only used to create a conjunct where the letter U+0A39 (ਹ) HA, U+0A30 (ਰ) RA or U+0A35 (ਵ) VA is the second element in a conjunct. More details in Section 3.3.2, "The Implicit Vowel Killer: Virama" in [Proposal-Gurmukhi].

Vowels and Matras: Punjabi has seven long vowels and three short vowels (ਅ /ə/, ਇ /I/, and ਉ /U/) . Each of them, except U+0A05 (ਅ) have a corresponding vowel sign, or matra, which is used to modify the vowel inherent in the preceding consonant. More details in Section 3.3.3, "Vowels" in [Proposal-Gurmukhi].

Bindi: Bindi represents a homo-organic nasal. Bindi is used with all long vowels and the short vowel U+0A09 (ਉ), as well as with the matras of long vowels, except the matra U+0A42 (ੂ). More details in Section 3.3.4.1, "The Bindi" in [Proposal-Gurmukhi].

Tippi: Tippi is used to nasalize short vowels /ə/ and /I/ at all places, as well as /U/ and /u/ after a consonant. Therefore, Tippi comes after consonants without a vowel sign (representing the matra of /ə/ "mukta") and after the matra of /I/ ( ਿ ) following vowel carriers and consonants, such as in ਸੰ and ਸਿੰ. The matras of /U/ ( ੁ,) and /u/ ( ੂ ) following a consonant also take a Tippi. In addition, Tippi is used in gemination for nasal consonants ਙ, ਞ, ਨ and ਮ. More details in Section 3.3.4.2, "The Tippi" in [Proposal-Gurmukhi].

Addak: Addak is used to mark the gemination of the following consonant. In Punjabi, addak usually can follow mukta, aunkar ( ੁ ) and sihari ( ਿ ), and the vowel signs of the short vowels /ə/, /u/ and /i/. It geminates the consonant that follows it; therefore it cannot occur at the end of a label. More details in Section 3.3.4.3 "The Addak" in [Proposal-Gurmukhi].

Nukta: Called pairin bindi in Punjabi, Nukta is used with the six consonants (ਸ, ਖ, ਗ, ਜ, ਫ and ਲ ) defined as set C1 to represent the phonemes of words of Sanskrit and Perso-Arabic sources. More details in Section 3.3.4.4, "Nukta" in [Proposal-Gurmukhi].

Common Digits: U+0030 (0) to U+0039 (9) are the set of digits from the ASCII range.

Whole Label Evaluation (WLE) and Context Rules

Common Rules

• Leading Combining Marks — restrictions on the allowable placement of combining marks (no leading combining mark). This rule is described in section 4.2.3.2 of RFC 5891 [150].

Default Actions

Actions include the default actions for LGRs as well as that needed to invalidate labels with misplaced combining marks. They are marked with ⍟. For a description see [RFC 7940].

Gurmukhi-specific Rules

These rules have been drafted to ensure that the prospective Gurmukhi label conforms to akshar formation norms as desired in Gurmukhi script. These norms are exclusively presented as context rules.

The following symbols are used in the WLE rules:
C → Consonant
M → Matra
V → Vowel
B → Bindi
D → Tippi
A → Addak
H → Virama / Halant
N → Nukta
M1 → { ਿ(U+0A3F), ੁ (U+0A41) } (Short matras)
M2 → M - M1 (Long matras)
V1 → { ਅ (U+0A05), ਇ (U+0A07), ਉ (U+0A09)} (Short Vowels)
V2 → V - V1 (Long Vowel)
C1 → {ਖ (U+0A16), ਗ (U+0A17), ਜ (U+0A1C), ਫ (U+0A2B), ਲ (U+0A32), ਸ (U+0A38)}
C2 → { ਰ (U+0A30), ਵ (U+0A35), ਹ (U+0A39)}
C3 → C – {ਙ (U+0A19), ਞ (U+0A1E), ਣ (U+0A23), ਹ (U+0A39), ੜ (U+0A5C)}

The rules are:

• 7.1 N: must be preceded by C1
• 7.2 H: must be preceded by C or N and followed by C2
• 7.3 M: must be preceded by C or N
• 7.4 B: must be preceded by specific V or M
• 7.5 D: must be preceded by C, N or specific V or M
• 7.6 A: must be preceded by C, N or specific V or M and followed by C3

More details in Section 7, "Whole Label Evaluation Rules (WLE)" in [Proposal-Gurmukhi].

Methodology and Contributors

This reference LGR for the Gurmukhi script for the 2nd Level has been developed by Michel Suignard and Asmus Freytag, based on the Root Zone LGR for Gurmukhi and information contained or referenced therein, see [RZ-LGR-4-Guru]. Suitable extensions for the second level have been applied according to the [Guidelines] with community input. The original proposal for a Root Zone LGR for the Gurmukhi script, that this reference LGR is based on, was developed by the Neo-Brahmi Generation Panel (NBGP). For more information on methodology and contributors to the underlying Root Zone LGR, see Sections 4 and 8 in [Proposal-Gurmukhi], as well as [RZ-LGR-Overview].

References

The following general references are cited in this document:

[Guidelines]

ICANN, "Guidelines for Developing Reference LGRs for the Second Level, (Los Angeles, California: ICANN, 27 May 2020),
https://www.icann.org/en/system/files/files/lgr-guidelines-second-level-06jan16-en.pdf

[EGIDS]

Expanded Graded Intergenerational Disruption Scale,
https://www.ethnologue.com/about/language-status
(Accessed on 13 Nov. 2017)

[Proposal-Gurmukhi]

Neo-Brahmi Generation Panel, "Proposal for a Gurmukhi Script Root Zone Label Generation Ruleset (LGR)", 22 April 2019,
https://www.icann.org/en/system/files/files/proposal-gurmukhi-lgr-22apr19-en.pdf

[RFC 7940]

Davies, K. and A. Freytag, "Representing Label Generation Rulesets Using XML", RFC 7940, August 2016,
http://www.rfc-editor.org/info/rfc7940

[RFC 8228]

A. Freytag, "Guidance on Designing Label Generation Rulesets (LGRs) Supporting Variant Labels", RFC 8228, August 2017,
https://www.rfc-editor.org/info/rfc8228

[RZ-LGR-Overview]

Integration Panel, "Root Zone Label Generation Rules - LGR-4: Overview and Summary", 5 November 2020 (PDF),
https://www.icann.org/sites/default/files/lgr/lgr-4-overview-05nov20-en.pdf

[RZ-LGR-4-Guru]

ICANN, Root Zone Label Generation Rules for the Gurmukhi Script (und-Guru) , 5 November 2020 (XML)
https://www.icann.org/sites/default/files/lgr/lgr-4-gurmukhi-script-05nov20-en.xml

[Unicode 6.3]

The Unicode Consortium. The Unicode Standard, Version 6.3.0, (Mountain View, CA: The Unicode Consortium, 2013. ISBN 978-1-936213-08-5)
http://www.unicode.org/versions/Unicode6.3.0/

For references consulted particularly in designing the repertoire for the Gurmukhi script for the second level please see details in the Table of References below. Reference [0] refers to the Unicode Standard version in which the corresponding code points were initially encoded. References [105] and above correspond to sources given in [Proposal-Gurmukhi] justifying the inclusion of the corresponding code points. Entries in the table may have multiple source reference values. Reference [150] indicates the source for common rules.

4.1 Character Classes

The following table lists all named and implicit classes with their definition and a list of their members intersected with the current repertoire (for larger classes, this list is elided).

4.2 Whole label evaluation and context rules

The following table lists all named rules defined in the LGR and indicates whether they are used as trigger in an action or as context (when or not-when) for a code point or variant.

4.3 Actions

The following table lists the actions that are used to assign dispositions to labels and variant labels based on the specified conditions. The order of actions defines their precedence: the first action triggered by a label is the one defining its disposition.